Discharge-type ignition device for oil burner

ABSTRACT

A discharge-type ignition device for an oil burner capable of permitting ignition of a wick to be carried out at any optimum position of the wick which is fixed. First and second discharge electrodes are arranged in proximity to the wick when it is raised to a combustion position. An ignition switch is kept turned on in the course of upward movement of the wick for ignition, so that spark discharge is generated between the discharge electrodes toward the wick being raised. The wick is raised to an uppermost position beyond the combustion position every time when the ignition operation is carried out, so that ignition may take place at any optimum position of the wick.

BACKGROUND OF THE INVENTION

This invention relates to a discharge-type ignition device for an oilburner, and more particularly to a discharge-type ignition device for anoil burner which is adapted to carry out ignition of a wick of the oilburner by electric discharge.

Conventionally, a filament-type ignition device for an oil burner whichis constructed so as to red-heat a filament by means of a dry cellacting as a power supply, to thereby permit the red-heated filament toignite a wick of the oil burner is generally used for ignition of theoil burner.

Further, a discharge-type ignition device for an oil burner is alsoknown in the art. The discharge-type ignition device is classified intoa device using combustion heat generated from the oil burner as a heatsource and a commercial AC 100 V power supply as a power supply for theignition device and a device using a battery means such as a dry cell asthe power supply.

The latter discharge-type ignition device using a battery as the powersource for electric or spark discharge is disclosed in Japanese UtilityModel Publication No. 35244/1988, although it unfortunately fails to beput into practice due to various disadvantages. The conventionaldischarge-type ignition device using a battery as disclosed includesdischarge electrodes arranged so as to be spaced from each other with acombustion wick being interposedly positioned therebetween.

The present invention is directed to a discharge-type ignition device ofthe latter type which uses a battery as a power supply to carry outspark discharge between discharge electrodes, to thereby ignite a wick.

The conventional discharge-type ignition device using a dry cell as thepower supply has a disadvantage that the dry cell fails to permit sparkdischarge sufficient for ignition of a wick of an oil burner to occurbetween discharge electrodes. Also, the conventional discharge-typeignition device using a dry cell causes a variation in height of thewick and deterioration of a surface of the wick due to settling of thewick, adhesion of tar to the wick or the like, and deformation of thewick with lapse of time, resulting in a variation in dimension betweenthe wick and the discharge electrodes. This causes spark generated bydischarge to be deviated from the wick, leading to a failure in ignitionof wick and/or generation of white fume of fuel oil from the wick. Thiswould be the reason why the conventional discharge-type ignition deviceusing a dry cell fails to be put into practice.

Thus, an ignition device for an oil burner which is currentlycommercially available is limited to the above-described filament-typeignition device.

Accordingly, it is highly desirable to develop a discharge-type ignitiondevice using a battery such as a dry cell which eliminates theabove-described disadvantage of the prior art, because it is essentiallyfree of a disadvantage of a filament-type ignition device that afilament is readily exhausted, deformed and/or broken.

SUMMARY OF THE INVENTION

The present invention has been made in view of the foregoingdisadvantage of the prior art.

Accordingly, it is an object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofgenerating spark discharge in the course of upward movement of a wickfor ignition of the wick, to thereby ensure positive and effectiveignition of the wick irrespective of using of a dry cell.

It is another object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofpositively accomplishing ignition of a wick irrespective of a variationin height of the wick, deterioration of the wick, deformation of thewick and the like.

It is a further object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofpositively carrying out ignition of a wick by spark discharge.

It is still another object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofeffectively accomplishing ignition of a wick even when spark dischargefor the ignition is weak, to thereby permit a small-sized power supplysuch as a dry cell to be used for the spark discharge.

It is even another object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofpreventing a human body such as a hand, a finger or the like fromcarelessly touching a discharge electrode means during cleaning of theignition device or the like.

It is a still further object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofkeeping a distance between a discharge electrode means and a wicksubstantially constant, to thereby ensure smooth ignition of the wick.

It is a yet further object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofeffectively preventing a side wind blowing against the oil burner fromadversely affecting both ignition operation and combustion operation.

It is an even further object of the present invention to provide adischarge-type ignition device for an oil burner which is capable ofbeing simplified in construction, leading to a decrease in manufacturingcost.

In accordance with the present invention, a discharge-type ignitiondevice for an oil burner is provided. The discharge-type ignition devicecomprises a wick receiving cylinder structure including an innercylindrical member and an outer cylindrical member arranged so as to bespaced from each other with a space being defined therebetween, a wickarranged in the space of the wick receiving cylinder structure so as tobe vertically movable, a wick operating shaft rotated for verticallymoving the wick, a discharge electrode means including a fist dischargeelectrode and a second discharge electrode which are arranged forgenerating spark discharge therebetween sufficient to ignite a portionof the wick raised so as to upwardly extend from the space of the wickreceiving cylinder structure, an ignition knob for rotating the wickoperating shaft in a wick raising direction, and an ignition switchoperated depending on actuation of the ignition knob. The ignitionswitch is turned off when the ignition knob is moved to a wick loweredposition and turned on in the course of upward movement of the wick andthe discharge electrode means carries out spark discharge in the courseof upward movement of the wick.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and many of the attendant advantages of thepresent invention will be readily appreciated as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings in which likereference numerals designate like or corresponding parts throughout;wherein:

FIG. 1 is a vertical sectional view showing an example of an oil burnerto which a discharge-type ignition device according to the presentinvention is applied;

FIG. 2 is a front elevation view showing an embodiment of adischarge-type ignition device for an oil burner according to thepresent invention which is at a wick ignition position;

FIG. 3 is a front elevation view of the discharge-type ignition deviceshown in FIG. 2 which is at a fire-extinguishing position;

FIG. 4 is a fragmentary enlarged sectional view showing an essentialpart of a discharge electrode means in the discharge-type ignitiondevice shown in FIG. 2;

FIG. 5 is a plan view of the discharge electrode means shown in FIG. 4;

FIG. 6 is a block diagram showing an electric circuit of thedischarge-type ignition device of FIG. 2;

FIG. 7 is a circuit diagram of each of an intermittent switch circuitand a high-voltage generation circuit in the circuit shown in FIG. 6;

FIG. 8 is a fragmentary sectional view showing a modification of adischarge electrode means;

FIG. 9 is a plan view of the discharge electrode means shown in FIG. 8;

FIG. 10 is a fragmentary sectional view showing another modification ofa discharge electrode means;

FIG. 11 is a plan view of the discharge electrode means shown in FIG.10;

FIG. 12 is a fragmentary sectional view showing a further modificationof a discharge electrode means;

FIG. 13 is a plan view of the discharge electrode means shown in FIG.12;

FIG. 14 is a fragmentary sectional view showing still anothermodification of a discharge electrode means; and

FIG. 15 is a plan view of the discharge electrode means shown in FIG.14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, a discharge-type ignition device for an oil burner according to thepresent invention will be described hereinafter with reference to theaccompanying drawings.

Referring first to FIG. 1, an example of an oil burner to which adischarge-type ignition device according to the present invention may beapplied is illustrated. The oil burner shown in FIG. 1 includes a wickreceiving cylinder structure 20 comprising an inner cylindrical member22 and an outer cylindrical member 24 arranged so as to be radiallyspaced from each other with a space being defined therebetween. In thethus-formed space of the wick receiving cylinder structure 20 isarranged a wick 26 in a manner to be vertically movable. The wickreceiving cylinder structure 20 is mounted on an oil reservoir 28.Reference numeral 30 designates a wick operating shaft, which is adaptedto vertically move the wick 26 when it is rotated. On the wick receivingcylinder structure 20 is supported a combustion cylinder structure 32 inwhich combustion of fuel oil takes place. The above-describedconstruction of the oil burner is widely known in the art.

Now, an embodiment of a discharge-type ignition device according to thepresent invention will be described hereinafter with reference to FIGS.1 to 5.

A discharge-type ignition device of the illustrated embodiment includesa discharge electrode means 34 comprising a pair of discharge electrodesor a first discharge electrode 34a and a second discharge electrode 34b.The first and second discharge electrodes 34a and 34b are arranged in amanner to be opposite to a side surface of the wick 26 and/or an upperend thereof. In the illustrated embodiment, the first dischargeelectrode 34a is a positive electrode and the second discharge electrode34b is a negative electrode. Also, in the illustrated embodiment, thefirst discharge electrode 34a and second discharge electrode 34b arearranged in proximity to the side surface of the wick 26 and opposite toan upper end surface of the wick with a gap being defined therebetween,respectively, when the wick 26 is raised to a normal combustionposition. The second discharge electrode 34b is preferably arranged inproximity to the upper end of the wick 26 when it is raised to anuppermost position defined beyond the combustion position.

The ignition device of the illustrated embodiment also includes anignition knob 36 vertically movably arranged and operatively engagedwith a lever 38 provided for rotating the wick operating shaft 30 and anignition switch 40 electrically connected to the discharge electrodemeans 34 to selectively feed it with electricity. In the illustratedembodiment, the ignition knob 36 is provided thereon with an arm-likeswitch actuator 42, so that downward movement of the ignition knob 36may permit the switch actuator 42 to actuate the ignition switch 40. Forthis purpose, the discharge-type ignition device may be so constructedthat the ignition switch 40 may be turned on in the course of upwardmovement of the wick 26. Such construction permits ignition of the wick26 to be carried out at any appropriate position of the wick which isnot fixed. The ignition knob 36 is connected to one end of a coiledcompression spring 44, resulting in being constantly biased toward anoriginal position thereof or in an upward direction as indicted atphantom lines in FIG. 2 and solid lines in FIG. 3 when it is moved to awick ignition position. The other end of the spring 44 may be connectedto any suitable portion of a body side of the oil burner. Alternativelyit is connected to a base plate 45 of the ignition device.

In addition, the discharge-type ignition device of the illustratedembodiment includes a rotation plate 46 fitted on the wick operatingshaft 30 so as to be rotated about the shaft 30. The rotation plate 46is provided with a holding section 48 for securely engaging the lever 38and rotation plate 46 with each other so as to permit both to beactuated in association with each other. Also, the rotation plate 46 isprovided with a lock section 50 which is adapted to be selectivelyengaged with the body side of the oil burner or the base plate 45 of theignition device to lock the wick at the combustion position, when thewick 26 is raised to the combustion position through rotation of thewick operating shaft 30. In the illustrated embodiment, the lock section50 is engaged with a stopper 52 of a vibration sensing means 54 whichmay be constructed in a manner widely known in the art. The lock section50 functions to lock the rotation plate 46 when it is engaged with thestopper 52 of the vibration sensing means 54. Thus, it will be notedthat the lock section 50 defines the combustion position. The locksection 50 may comprise a part of a cutout 56 formed at a periphery ofthe rotation plate 46. More particularly, in the illustrated embodiment,the lock section 50 comprises a front side surface of the cutout 56defined on the basis of rotation of the rotation plate 46 in a wickraising direction opposite to a direction indicated at an arrow 58.

Further, the discharge-type ignition device of the illustratedembodiment includes a rotation stopper 60 for stopping further rotationof the wick operating shaft 30 in the wick raising direction to preventfurther raising of the wick when the wick is raised to an uppermostposition defined somewhat beyond or above the normal combustionposition. In the illustrated embodiment, the rotation stopper 60comprises a rear side surface of the cutout 56 defined on the basis ofrotation of the rotation plate 46 in the wick raising direction oppositeto the direction indicated at the arrow 58. Thus, it will be noted thatthe rotation stopper 60 defines the uppermost position. In FIG. 2, thewick is raised to the uppermost position through the wick operatingshaft 30, resulting in the rotation stopper 60 being abutted against thestopper 52 of the vibration sensing means 54, to thereby prevent furtherraising of the wick 26 beyond the uppermost position. Thus, the rotationstopper 60 is defined opposite to the lock section 50 of the rotationplate 46. Alternatively, the rotation stopper 60 may comprise a memberengaged with the lever 38 to lock it when the wick is raised to theuppermost position.

Reference numeral 62 designates a wick lowering spring for constantlybiasing the rotation plate 46 in a wick lowering direction indicated atthe arrow 58. For this purpose, the wick lowering spring 62 is connectedat one end thereof to the rotation plate 46 and at the other end thereofto the base plate 45 of the ignition device. The wick lowering spring 62acts to forcibly rotate the rotation plate 46 and therefore the wickoperating shaft 30 in the wick lowering direction through the holdingsection 48. Normally, the lock section 50 of the rotation plate 46 isengaged with the stopper 52 of the vibration sensing means 54 to preventthe rotation plate 46 from being rotated due to elastic force of thewick lowering spring 62.

The vibration sensing means 54 includes a vibration sensing weight 64which is adapted to be actuated to release engagement between thestopper 52 of the vibration sensing means 54 and the lock section 50 ofthe rotation plate 46 when vibration of a predetermined level or more isapplied thereto, so that the wick 26 may be forcibly lowered to afire-extinguishing position through the rotation plate 46, lever 38 andwick vertically moving shaft 30 due to elastic force of the spring 62.

Reference numeral 66 designates a wick operating or vertically movingknob which may be arranged independent from the ignition knob 36 so asto operate or vertically move the wick 26. In the illustratedembodiment, it is disposed below the ignition knob 36 in a manner to bein proximity thereto, so that the ignition operation and wick verticallymoving operation may be carried out through the ignition knob 36 andwick operating knob 66, respectively. The wick operating knob 66 isdownwardly moved with the ignition knob 36 when the ignition operationis carried out. Alternatively, the wick operating knob 66 may beeliminated, wherein the ignition knob may act also as the wick operatingknob. In this instance, both operations may be carried out through onlythe ignition knob. The wick operating shaft 30, ignition knob 36 and thewick operating knob 66 are mounted on the base plate 45. The base plate45 is provided with a slide aperture 68, along which the knobs 36 and 66are vertically moved. Reference numeral 69 (FIG. 1) designate a wickdrive lever for converting rotation of the wick operating shaft 30 intoa vertical movement of the wick 26.

Now, the manner of operation of the discharge-type ignition device ofthe illustrated embodiment constructed as described above will bedescribed hereinafter.

When the ignition knob 36 is downwardly moved to rotate the wickoperating shaft 30 in the wick raising direction, the wick operatingshaft 30 raises or upwardly moves the wick 26 until the rotation stopper60 is abutted against the stopper 52 of the vibration sensing means 54,so that the wick is raised to the uppermost position, resulting in anupper end of the wick 26 being projected upwardly from the space of thewick receiving cylinder structure or between the inner cylindricalmember 22 and the outer cylindrical member 24, during which operation ofthe ignition knob 36 permits the ignition switch 40 to be turned on.This results in spark discharge being generated without interruptionbetween the discharge electrodes 34a and 34b in the course of upwardmovement of the wick 26, so that ignition of the wick may beaccomplished when a relative position between the wick 26 and thepositive discharge electrode 34a is rendered optimum to the ignition.

The ignition knob 36 is provided separate from the lever 38 for rotatingthe wick operating shaft 30; so that when the ignition knob 36 isreleased from a hand of an operator after ignition of the wick 26, it isreleased from the lever 38 by the compression spring 44, resulting inbeing returned to an original position thereof as shown in FIG. 3.Concurrently, the ignition knob 36 turns off the ignition switch 40 tostop the spark discharge and the ignited wick 26 is kept at thecombustion position.

The holding section 48 of the rotation plate 46 causes the rotationplate 46 to be moved with the wick operating shaft 30. Therefore, whenthe wick operating shaft is rotated in the wick raising direction, therotation plate 46 is rotated against the wick lowering spring 62 throughthe combustion position at which the lock section 50 of the rotationplate 46 is engaged with the stopper 52 of the vibration sensing means54 to the uppermost position at which the rotation stopper 60 is abuttedagainst the stopper 52. Then, when the ignition knob 36 is released froma hand of an operator, the wick lowering spring 62 causes the rotationplate 46 to be somewhat returned to the position at which the locksection 50 is engaged with the stopper 52 of the vibration sensing means54, so that the wick 26 may be moved to the normal combustion position,resulting in combustion of the oil burner being continued. Thus, thewick 26 is constantly moved to the uppermost position beyond thecombustion position every time when the ignition operation takes place,therefore, it is positively and effectively ignited irrespective of avariation in height of the wick 4, deterioration of the wick,deformation of the wick and the like.

As can be seen from the foregoing, the discharge-type ignition device ofthe illustrated embodiment is so constructed that spark dischargebetween the discharge electrodes 34a and 34b is carried out in thecourse of upward movement of the wick 26 for the ignition andcombustion, resulting in ignition of the wick being positively andeffectively carried out at any optimum position irrespective of avariation in height of the wick, deterioration of the wick and the like.Also, the ignition knob 36 is arranged separate from the lever 38 forrotating the wick operating shaft 30 and the ignition knob 36 isconnected to the compression spring 44 for biasing it to the originalposition, so that spark discharge may be interrupted during thecombustion operation, to thereby accomplish the ignition with highreliability.

Further, the normal combustion position of the combustion wick 26 iskept substantially constant, however, the wick is gradually deterioratedwith repeating of the combustion operation. The illustrated embodimentis so constructed that the wick is moved to the uppermost positionbeyond the combustion position while the ignition switch is kept turnedon, every time when the ignition operation is carried out, resulting inan upper portion of the wick which is easy to be ignited entering withina spark discharge range, leading to an improvement in ignitionperformance.

Now, an electric circuit of the discharge-type ignition device of theillustrated embodiment will be described hereinafter with reference toFIGS. 6 and 7, wherein FIG. 6 generally shows an electric circuit of thedischarge ignition device of the illustrated embodiment and FIG. 7 showsan example of a circuit construction of each of a high-voltagegenerating circuit 70 and an intermittent switch circuit 72 in thecircuit shown in FIG. 6.

Reference numeral 74 designates a battery means such as a dry cell orthe like acting as a power supply for spark discharge, which batterymeans may be arranged so as to generate a voltage of 6 V. The ignitionswitch 40 is kept turned on in the course of upward movement of the wickto the uppermost position beyond the combustion position and at theuppermost position every time when the ignition operation is carriedout. A period of time during which the ignition switch 40 is kept turnedon may be varied by varying a length of the switch actuator 42 describedabove. Reference character C1 designates an electrolytic capacitor. Theintermittent switch circuit 72 includes transistors TR1 to TR3,resistors R1 to R4, and capacitors C1 and C2. A transistor TR3constitutes a semiconductor switch arranged in the middle of aconnection line through which the power supply 74 is connected to thehigh-voltage generation circuit 70. The transistor TR3 acts as thesemiconductor switch for a period of time during which the ignitionswitch 40 is kept turned on. Also, a signal generation circuit isprovided which is adapted to feed the transistor TR3 with an on-offsignal at a predetermined cycle. The signal generation circuit may beconstituted by a multivibrator. In the illustrated embodiment, a valueof each of the resistors R1 to R4 and capacitors C1 and C2 is so setthat the transistor TR3 is kept turned on for two seconds and turned offfor one second. The high voltage generation circuit 70 is kept connectedto the power supply 74 during a period of time for which the transistorTR3 is kept turned on.

The high-voltage generation circuit 70 includes a signal generationcircuit constituted by a multivibrator comprising resistors R5 to R8,capacitors C4 and C5, and transistors TR4 and TR5; a switching circuitcomprising resistors R9 and R10, transistors TR6 and TR7, and a diode D;and a step-up transformer T and a capacitor C6. In the illustratedembodiment, a value of each of the resistors R5 to R8 and capacitors C4and C5 is so set that an oscillation frequency of the signal generationcircuit is 750 Hz. The transistors TR6 and TR7 are kept turned on for aperiod of time during which the transistor TR5 is kept turned off, tothereby permit a current to flow through a primary winding W1 of thetransformer T. When the transistor TR5 is kept turned on, thetransistors TR6 and TR7 are kept turned off, resulting in flowing of acurrent through the primary winding W1 of the transformer T beinginterrupted, leading to generation of a high voltage across a secondarywinding W2 of the transformer T. The high voltage thus generated isapplied between the discharge electrode 34a and 34b, so that sparkdischarge occurs therebetween.

In the illustrated embodiment, spark discharge between the dischargeelectrodes 34a and 34b is repeated for a period of time during which thetransistor TR3 of the intermittent circuit 8 is kept turned on and isinterrupted for a period of time during which it is kept turned off.

Also, in the illustrated embodiment, the second discharge electrode 34bmay be grounded. At least one of the discharge electrodes 34a and 34bmay be arranged so as to be contacted with or positioned in the wickwhen the wick is upwardly moved to the combustion position.

Referring now to FIGS. 8 and 9, a modification of the dischargeelectrode means incorporated in the discharge-type ignition device ofthe illustrated embodiment described above is illustrated. Themodification is adapted to prevent a human body such as a hand or thelike from being shocked due to careless touch with a discharge electrodemeans. A discharge electrode means of the modification which isgenerally designated at reference numeral 34 includes a first dischargeelectrode 34a mounted through an insulator 76 mounted on a collar of anupper end of an outer cylindrical member 24 of a wick receiving cylinderstructure 20. The first discharge electrode 34a is arranged so as to beopposite to a side surface of a wick 26 or an upper end thereof when anupper portion of the wick is upwardly projected from the wick receivingcylinder structure due to upward movement of the wick for ignition.

The discharge electrode means 34 also includes a second dischargeelectrode 34b formed so as to surround at least one of an upper portionof the first discharge electrode 34a and a peripheral portion thereof.For this purpose, the second discharge electrode 34b may be formed of awire of, for example, about 5 mm in diameter into an inverted U-shape.Also, the second discharge electrode 34b thus formed is arranged in amanner to upwardly extend from the outer cylindrical member 24 of thewick receiving cylinder structure 20 while being contactedly positionedat one end thereof on the outer cylindrical member 24, bent or folded atan intermediate portion thereof so as to straddle the upper portion ofthe wick 26, and contacted at the other end thereof with an innersurface of the wick 26 when it is raised to the combustion position.Such formation and arrangement of the wick 26 permit spark discharge tooccur at the upper portion of the wick 26 surrounded by the seconddischarge electrode 34b as shown in FIGS. 8 and 9, so that a human bodysuch as a hand or the like may be effectively prevented from touchingboth discharge electrodes 34a and 34b even when the ignition switch isturned on by mistake or carelessly, for example, during cleaning of theignition device. Thus, the discharge electrode means of the modificationeffectively prevents a human body from being shocked due to the touchwith the electrodes.

Also, the modification is so constructed that at least one of thedischarge electrodes is arranged so as to be contacted with the wickwhen it is raised to the combustion position. Such construction permitsa distance between the discharge electrode means and the wick 26 to bekept substantially constant, to thereby ensure smooth ignition of thewick.

The remaining part of the modification may be constructed insubstantially the same manner as the discharge electrode means in theabove-described embodiment.

Referring now to FIGS. 10 and 11, another modification of the dischargeelectrode means is illustrated. A second discharge electrode 34b isformed of a thin plate material and arranged in a manner to be extendedfrom below a first discharge electrode 34a. The second dischargeelectrode 34b is formed at a portion thereof opposite to the firstdischarge electrode 34a with an aperture 78. Then, the second dischargeelectrode 34b is is bent at an upper portion toward the first dischargeelectrode 34a while being kept contacted therewith. Such formation andarrangement permit the second discharge electrode 34a to surround aperiphery of the first discharge electrode 34a. Thus, it will be notedthat the modification exhibits the same advantage as the firstmodification described above.

Referring now to FIGS. 12 and 13, a further modification of thedischarge electrode means is illustrated. A discharge electrode means ofthe illustrated modification which is generally designated at referencenumeral 34 includes a first discharge electrode 34a mounted on aradiation plate 80 provided on an outer cylindrical plate 24 of a wickreceiving cylinder structure 20. The first discharge electrode 34a is soarranged that a distal end thereof is opposite to a side surface of anupper portion of a wick 26 through a through-hole 82 formed at an upperedge section 84 of the outer cylindrical member 24 when the wick 26 israised to the combustion position. The upper edge section 84 is arrangedso as to be positioned above an upper end of the inner cylindricalmember 22 and horizontally outwardly spaced from the wick 26. Thethrough-hole 82 is formed by cutting out a part of the upper section 84of the outer cylindrical member 24, so that a cutout element 86 isformed at the upper edge section 84. The discharge electrode means 34also includes a second discharge electrode 34b arranged opposite to thefirst discharge electrode 34a. The second discharge electrode 34b isgrounded at one end thereof through the outer cylindrical member 24.Arrangement of the second discharge electrode 34b in a manner oppositeto the first discharge electrode 34a may be carried out by horizontallyextending the above-described cutout element 86 toward the wick andbending a distal end portion 87 of the cutout element 86 so as tovertically extend therefrom. This permits the distal end portion 87 toact as the second discharge electrode 34b.

The first discharge electrode 34a may be tightly fitted in thethrough-hole 82 of the upper end section 84 of the outer cylindricalmember 24 through the insulator 76. The radiation plate 80 is arrangedso as to outwardly extend from below the upper edge section 84 of theouter cylindrical member 24, resulting in heat of the outer cylindricalmember 24 being outwardly discharged through the radiation plate. Also,the radiation plate 80 acts to prevent a side wing blowing against theoil burner from adversely affecting both ignition and combustionoperations. For this purpose, the radiation plate 80 is formed into anannular dish-like shape, resulting in including a horizontal section 88and a vertical section 90 formed at an outer periphery of the horizontalsection 88. The insulator 76 may be supported on the horizontal section88 of the radiation plate 80. Alternatively, the insulator may besecurely mounted on the horizontal section 88 by means of a band 92. Thevertical section 90 of the radiation plate 80 is formed with athrough-hole 94 in a manner to be positionally aligned with thethrough-hole 82 of the outer cylindrical member 24, so that the firstdischarge electrode 34a may be closely inserted through thethrough-holes 82 and 94. Such construction further prevents a side windblowing against the oil burner from adversely affecting both ignitionoperation and combustion operation, because the insulator tightly fittedin the through-holes 82 and 94 prevents the wind from blowingtherethrough. Reference numeral 95 designates a screw for fixing theinsulator 76 on the horizontal section 88 of the radiation plate 80.

Thus, the modification effectively prevents a side wind blowing againstthe oil burner from adversely affecting both ignition operation andcombustion operation. Also, the cutout element 86 of the upper edgesection 84 of the outer cylindrical member 24 of the wick receivingcylinder structure 20 may is constructed so as to act as the seconddischarge electrode, resulting in a construction of the ignition devicebeing simplified, leading to a decrease in cost.

Referring now to FIGS. 14 and 15, still another modification of thedischarge electrode means is illustrated. In the illustratedmodification, an outer cylindrical member 24 and and inner cylindricalmember 22 are formed so as to be different in height of an upper endthereof from each other. One of the outer and inner cylindrical membersof which the upper end has a larger height is mounted thereon with afirst discharge electrode 34a of a discharge electrode means 34 throughan insulator 76. In the modification, the outer cylindrical member 24 isformed so as to upwardly extend at the upper end thereof beyond theinner cylindrical member 22.

More particularly, the first discharge electrode 34a of the dischargeelectrode means 34 is mounted through an insulator 76 on an upper edgeportion 84 of the outer cylindrical member 24 of a wick receivingcylinder structure 20. The first discharge electrode 34a is arranged soas to extend toward a wick 26. Also, the first discharge electrode 34ais vertically bent at a distal end portion thereof, resulting in beingformed with a vertically extending parallel section 96 arranged inparallel to the wick 26 when it is raised to a combustion position. Thedischarge electrode means 34 also includes a second discharge electrode34b mounted on the outer cylindrical member 24 in proximity to the firstdischarge electrode 34a. The second discharge electrode 34b is likewisearranged so as to extend toward the wick 26. Also, the second dischargeelectrode 34b is bent at a distal end thereof, to thereby be formed witha vertically extending parallel section 98 arranged in parallel to thewick 26 when it is raised to a combustion position, as well as inparallel to the vertically extending parallel section 96 of the firstdischarge electrode 34a. In the illustrated modification, the parallelsections 96 and 98 are formed so as to upwardly extend. However, theymay be arranged so as to downwardly extend.

At least one of the parallel sections 96 and 98 of the first and seconddischarge electrodes 34a and 34b is preferably arranged so as to becontacted with the wick 26 or positioned therein. Also, the parallelsections are preferably upwardly enlarged or spread.

Reference numeral 100 designates a guard which is formed so as toupwardly extend beyond the first and second discharge electrodes 34a and34b. The guard 100, when the discharge electrode means 34 is disposedbetween the outer cylindrical member 24 and the wick 26, is arrangedinside the wick 26. In this instance, the guard 100 is inside an innercylinder 102 of a combustion cylinder construction. Whereas, it isarranged between the outer cylindrical member 24 and the wick 26 whenthe discharge electrode means is disposed inside the wick 26. In thisinstance, the guard 100 is arranged outside an outer cylinder 104 of thecombustion cylinder construction 32. The guard 100 is conveniently madeof a punched plate. The guard 100 serves as a protective means forpreventing a human body such as a hand or the like from touching thedischarge electrode means 34 by mistake during cleaning of the ignitiondevice or the like.

As described above, the ignition device of the illustrated modificationis so constructed that the vertically extending parallel sections 96 and98 of the discharge electrodes 34a and 34b each are arranged so as to becontacted with or positioned in the wick. Such construction ensurespositive ignition of the wick. Also, arrangement of the guard 100effectively prevents a human body from being shocked due to touch withthe discharge electrode means.

While a preferred embodiment of the invention has been described with acertain degree of particularity with reference to the drawing, obviousmodifications and variations are possible in light of the aboveteachings. It is therefore to be understood that within the scope of theappended claims, the invention may be practiced otherwise than asspecifically described.

What is claimed is:
 1. A discharge-type ignition device for an oilburner, comprising:a wick receiving cylinder structure including aninner cylindrical member and an outer cylindrical member arranged so asto be spaced from each other with a space being defined therebetween; awick arranged in said space of said wick receiving cylinder structure soas to be vertically movable; a wick operating shaft rotated forvertically moving said wick; a discharge electrode means including afirst discharge electrode and a second discharge electrode which arearranged for generating spark discharge therebetween sufficient toignite a raised portion of said wick raised so as to upwardly extendfrom said space of said wick receiving cylinder structure; an ignitionknob for rotating said wick operating shaft in a wick raising direction;and an ignition switch operated depending on actuation of said ignitionknob; said ignition switch being turned off when said ignition knob ismoved to a wick lowered position and turned on in the course of anupward movement of said wick; one of said first and second dischargeelectrodes being arranged in a manner to be in substantial contact withsaid wick during said upward movement thereof; and said ignition switchcausing said discharge electrode means to carry out said spark dischargeduring said upward movement of said wick.
 2. A discharge-type ignitiondevice as defined in claim 1, wherein said ignition knob is providedseparate from said wick operating shaft;said ignition knob turns on saidignition switch at a combustion position at which combustion is carriedout as well as in the course of said upward movement of said wick; andsaid ignition knob is constantly urged toward an original position.
 3. Adischarge-type ignition device as defined in claim 2, further comprisinga rotation stopper for preventing said wick operating shaft from beingrotated beyond an uppermost position defined beyond said combustionposition; anda rotation plate fittedly mounted on said wick operatingshaft so as to be rotatable about said wick operating shaft; saidrotation stopper being arranged in association with one of said wickoperating shaft and rotation plate; said rotation plate being formedwith a holding section for holding said rotation plate on said wickoperating shaft to move said rotation plate with said wick operatingshaft and a lock section for locking said rotation plate at saidcombustion position; said rotation plate having connected thereto a wicklowering spring for biasing said rotation plate locked at saidcombustion position in a wick lowering direction; and said wickoperating shaft being rotated to said uppermost position beyond saidcombustion position every time when an ignition operation is carriedout, during which said spark discharge is generated.
 4. A discharge-typeignition device as defined in claim 2, wherein at least one of saidfirst and second discharge electrodes is arranged so as to be constantlyin substantial contact with said wick when said wick is positioned atthe combustion position.
 5. A discharge-type ignition device as definedin claim 1, further comprising a high-voltage generation circuit forapplying, between said first discharge electrode and said seconddischarge electrode, a high voltage sufficient to permit spark dischargeto be generated between said discharge electrodes;a battery means forfeeding a DC power to said high-voltage generation circuit through saidignition switch; and an intermittent switch circuit arranged betweensaid ignition switch and said high-voltage generation circuit so as tobe operated at a predetermined cycle for a period of time during whichsaid ignition switch is kept turned on, to thereby permit a current tobe intermittently fed from said battery means to said high-voltagegeneration circuit.
 6. A discharge-type ignition device as defined inclaim 5, wherein said intermittent switch circuit includes asemiconductor switch arranged in the middle of a connection line throughwhich said battery means and high-voltage generation circuit areconnected to each other and a signal generation circuit for outputtingan on-off signal to said semiconductor switch at a predetermined cyclefor a period of time during which said ignition switch is kept turnedon.
 7. A discharge-type ignition device as defined in claim 1, whereinat least one of said first and second discharge electrodes is arrangedso as to be positioned in the wick when the wick is positioned at thecombustion position.
 8. A discharge-type ignition device as defined inclaim 1, wherein said second discharge electrode is arranged so as tosurround at least one of an upper portion of said first dischargeelectrode and a periphery thereof;at least one of said dischargeelectrodes being arranged so as to be constantly in substantial contactwith said raised portion of said wick.
 9. A discharge-type ignitiondevice as defined in claim 1, wherein said outer cylindrical member ofsaid wick receiving cylinder structure is provided with an upper edgesection;said upper edge section being formed with a through-hole bycutting out a part thereof, resulting in a cutout element being formedat said upper edge section; and said cutout element horizontallyextending toward said wick and being bent at a distal end portionthereof so as to vertically extend, so that said distal end portion mayact as said second discharge electrode.
 10. A discharge-type ignitiondevice as defined in claim 1, wherein said outer cylindrical member andinner cylindrical member are arranged so as to be different in height atan upper end thereof from each other;one of said outer and innercylindrical members of which the upper end has a larger height havingmounted thereon said first discharge electrode through an insulator;said first discharge electrode being formed at a distal end thereof witha vertically extending parallel section which is parallel to said wick;and said second discharge electrode being formed at a distal end thereofwith a vertically extending parallel section which is parallel to saidwick and said parallel section of said first discharge electrode.
 11. Adischarge-type ignition device as defined in claim 10, wherein at leastone of said parallel sections of said first and second dischargeelectrodes is arranged so as to be constantly in substantial contactwith said raised portion of said wick.
 12. A discharge-type ignitiondevice as defined in claim 10, wherein at least one of said parallelsections of said first and second discharge electrodes is arranged so asto be positioned in said raised portion of said wick.
 13. Adischarge-type ignition device as defined in claim 11, wherein saidparallel sections of said first and second discharge electrodes areformed to upwardly extend while being upwardly enlarged.
 14. Adischarge-type ignition device as defined in claim 11, furthercomprising a guard arranged in a manner to be opposite to said dischargeelectrode means with said wick being interposed between said guard andsaid discharge electrode means.
 15. A discharge-type ignition device asdefined in claim 12, wherein said parallel sections of said first andsecond discharge electrodes are formed to upwardly extend while beingupwardly enlarged.
 16. A discharge-type ignition device as defined inclaim 12, further comprising a guard arranged in a manner to be oppositeto said discharge electrode means with said wick being interposedbetween said guard and said discharge electrode means.
 17. Adischarge-type ignition device as defined in claim 1, wherein at leastone of said first and second discharge electrodes is arranged so as tobe constantly in substantial contact with said raised portion of saidwick.
 18. A discharge-type ignition device as defined in claim 1,wherein at least one of said first and second discharge electrodes isarranged so as to be positioned in said raised portion of said wick.